Hot migration of a virtual machine is a key technology in the virtualization field, and is a significant means to implement dynamic resource scheduling for a virtual cluster, hitless service change, and host maintenance. A fundamental principle of the hot migration of a virtual machine is: migrating a running virtual machine from a source physical machine to a destination physical machine in a case in which a service of a user is not affected or a user is unaware of the migration. In order to quickly implement integration of a hot resource and a power supply, each time multiple virtual machines may need to be determined to be migrated. A current policy is calculating, according to the number of virtual machines for concurrent migration of a host and with reference to an average value of historical migration duration time of virtual machines, the maximum number of virtual machines for migration that are accommodated in each host. However, a deviation in migration duration time is relatively large because of a difference in specifications and services. Therefore, assessment of the migration duration time is inaccurate and a proper decision on the hot migration of a virtual machine cannot be made.